Telephone-circuit.



Pathted Nov. 28, I899.

.1. J. MOLLER. TELEPHONE CIRCUIT.

(Application filed June 2, 1898A (No Model.)

NITED' STATES,

PATENT OFFICE.

JoRGEN JAOOBSEN MoLLER, or KIEL, eERMANY.

TELEPHONE-CIRCUIT.

SPECIFICATION forming part of Letters Patent No. 637,884, dated November 28, 1899. Application filed tuner, 1893. Serial No. 476,328. (No model.)

To all whom it may concern:

Beit known thatI, J oReEN J ACOBSEN MoL- LER, a subject of the German Emperor, residing at Kiel, in the Province of Schleswig- Holstein, in the Empire of Germany, have invented certain new and useful Improvements in Telephone-Circuits; and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same, reference beinghad to the accompanyingdrawings, and to letters and figures of reference marked thereon, which form a part of this specification.

My invention relates to improvements in telephone systems; and it has for its object the provision of means whereby the receivers remain in circuit during calling without loss of call-bell or battery current or any interference with the call-bell or battery circuit and at the same time enables the sender to ascertain if the receiver is busy, as will now be described, reference being had to the accompanying drawing, which shows a diagrammatic view of a telephone system embodying my invention.

The line-wire L is directly connected to the automatic switch or hand-phone-carrying lever A at the point 1, said lever having a hook at one end, on which is hung the receiver F and the other end contacts with two points 3 and 5, alternately connecting the receivers and the bell W to line, and between these points is an insulated projection 19, which contacts with the lever 71 and closes the primary microphone-circuit, which includes the battery B or other source of electromotive force.

The receiver-circuit is connected at one end with the contact 3 and at the other to the fulcrum s of the call lever f, which is normally in contact with the grounded point 5 through wires k t g.

The call-battery B, grounded by wires 0 i g, is connected to line by wire a, point 5, and lever f. A lightning-arrester S is placed in parallel with the instrument. One or more receivers F F may be placed in the receiving-circuit.

To call, the person takes the receiver from its hook, the point p acting on the lever 1%,

thereby closing the primary or microphone circuit at 2 m battery B, wire m, microphone M, wire or, primary winding of the induction-coil J, wire m point 4, and lever '17., at the same time breaking the bell-circuit at 5 and connecting the receiver-circuit at 3 3 to line. The call-lever f is now depressed, sending current from battery B, lever f, wire 70 receivers F F, secondary of the inductioncoil,wire k,contacts 3 3 ,1everA,wire Z),to line L and called station, where the line L enters through wire I) and fulcrum 1, sending current through lever A, contact 5, wire 6, bell IV, wire g, to ground. The sender, by placing the receivers to his ear, can hear a vibration of the diaphragms in the receivers, due to the intermittent current in the line caused by the make and break at the bell of the called station.

Should the receiver at the called station be off its book, the current will be grounded without passing through the bell W. Ourrent in this case enters the called station from 7 5 the line L at 1, and via A 3 3 is J k, receivers, to lever f s? it ig, to ground. A steady current will fiow in this case, because it will not pass through a circuit-breaker, (the bell,) and no sound will be heard at the sending- 8o station.

Having thus described my invention, what I claim as new therein, and desire to secure by Letters Patent, is-- 1. In a telephone system, the combination with the main line, of a signal branch permanently grounded, a hand-phone-carrying lever normally connecting the latter to the main line, a three-point switch normally grounded, a branch in parallel with the signal branch including a hand-phone, terminating at the three-point switch and adapted to be connected to line through said hand-phonecarrying lever, and a subbranch permanently grounded and adapted to be connected to line through said three-point switch branch containing the hand-phone and hand-phonecarrying lever, substantially as set forth.

2. In a telephone system, the combination with the main line, of a signal branch permanently grounded, a hand-phone-carrying lever normally connecting the latter to the main line, a three-point switch normally grounded, a branch in parallel with the signal branch including a hand-phone and secondary coil of a local talking-circuit, terminating at the three-point switch and adapted to be connected to line through said hand-phonecarrying lever, a two-point switch mechanicaliy operated by said hand-phone-carrying lever and closing a local circuit containing a battery, microphone and primary of the induction-coil, and a subbranch permanently 1o grounded and adapted to be connected to line through said three-point switch branch 

